Solenoid valves can be activated by current flowing through a coil to create an electromagnetic field that causes movement of an armature within the valve. Solenoid control valves for hydraulic control systems can be used to control fluid under pressure, such as to switch latch pins in switching lifters and lash adjusters in engine valve systems.
A solenoid valve can be energized to permit fluid to flow through a control passage to the hydraulic component. The time to fill the control passage with pressurized fluid slows the desired response of the component. Additionally, if air is permitted to enter the control passage, actuation of the component by the fluid can be slower or less precise.